But they found the plant's large leaves are the key to its success,because they are covered in microscopic streams through which water canbe channelled.

Scientists claim ridges in the leaves act like mountain valleys,funnelling the water slowly and directly into the plant while stoppingit evaporating.

A team from the Department of Science Education-Biology at theUniversity of Haifa-Oranim, in Israel, said the leaves act like a miniirrigation system.

Lead researcher Professor Gidi Ne'eman said "We know of no other plantin the deserts of the world that functions in this manner.

"We have managed to make out the 'self-irrigating' mechanism of thedesert rhubarb, which enables it to harvest 16 times the amount ofwater than otherwise expected for a plant in this region based on thequantities of rain in the desert.

"These deep and wide depressions in the leaves create a "channelling"mountain-like system by which the rain water is channelled toward theground surrounding the plant's deep root.

"Other desert plants simply suffice with the rain water that penetrates the ground in its immediate surroundings."

Results of experiments and analysis of the plant's growth – in an areawith an average annual rainfall of 75mm – showed that the desertrhubarb is able to harvest quantities of water that are closer to thatof Mediterranean plants, reaching up to 426mm per year.

That is 16 times the amount of water harvested by the small-leafed plants of the Negev desert region.